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Bravo Audio - funny looking little tube amps

Discussion in 'Headphone Amps (full-size)' started by ear8dmg, Sep 9, 2009.
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  1. UmustBKidn
     
    A lot of the questions you're asking have been discussed earlier in this thread. Yeah, I know, it's a long thread. I've been participating in it for a little over a year. I did not read from the beginning, but I've hit a few sections in the middle.
     
    Here is a thread discussing mods, including some discussion of tubes.
     
    Here is a review I wrote comparing the Bravo V2 vs the Schiit Magni, using the Pure i-20 DAC and Schiit Modi DAC.
     
    You should visit these boards if you're considering modifying your amp. Note that's a different website.
     
    I've got two V2's, one which I just brought back from the dead, after modifying it. Tubes can help open up the high end (telefunken ECC82's in particular), but you really need to replace the MOSFETs if you truly want the high end improved. I'm still tinkering with it, and will write more about it after I'm done. I'm partial to Mullards myself, and I'm really anxious to see what this modified amp sounds like with a vintage Mullard in it.
     
  2. Coolmeadow Kid
    Sorry for not posting a reply UmustBKidn.  I opened a new thread on the tubes, and hadn't been back over here.  I read the whole thread once before posting much.  Just this weekend, I've skipped through the first 45 or so pages, and read  through the remaining 120 or so pages  pretty closely looking for specific information.  I ordered 3 tubes 2 weeks ago. First, a Baldwin re-branded Sylvania green label long grey plate halo getr.  I liked it a lot! Still not quite the bass I was looking for. The next 2 came together, a Black long plate RCA square angled getr from 53 or 54, that didn't do much for me.  Definitely better that the supplied tube, but still weak in the bass department. And a Black long plate Baldwin yellow label re-branded Raytheon with halo getr that is the best of the lot!!  Much better bass that is tight.  Good mids and highs and decent sound stage. 
    After re-reading the thread this weekend, I ordered 2 RCA clear tops to try, since several people said they worked very well in the V2 and had really good bass.  I also copied info on the different modifications recommended for these, and I'm contemplating doing that also.  Just finished up an Oak housing for the amp that incorporates an 80mm computer fan to help cool things down. This has been running for about 15 minutes and the heat sinks are not hot at all.  I can grab both sides and hold on with no notice of heat. It will be a little more involved to roll tubes, but just a couple minutes.  May have to rebuild it if I do the mods, depending on the caps I go with and where they have to be mounted to fit I may need a little more height than I have right now.  But I'll cross that road later.
    Thanks for your help.  I enjoyed reading your posts.  Jim.
     
     

     
  3. UmustBKidn
     
    No worries bro, glad they were of some help.
     
    I have since brought my modified Bravo to the other location where I keep the unmodified unit and plugged it inline with my Schiit Modi DAC, and my Beyerdynamic DT770's. It's a bit less impressive on this setup, than listening on my low end ATH M40's (note that's not a typo - the M40's are cheap compared to the M50's). I hear a lot of top end on this setup, but noticeably less bass response. It is unclear if the less bass response is due to just having more high end or not. I am wondering what effect that modifying the output capacitors from 1000 uF to 2200 uF has on this.
     
    The main thing that moving it gave me was the ability to roll in some of my vintage Mullards (they're all in this other location). I note with some curiosity that the use of a 1957 D-getter Mullard has not produced an abundance of bass response. I have decided to leave it sit in this setup for a while and get used to it, then swap in the unmodified Bravo V2 (with a similar old Mullard in it), to see what the difference is.
     
    (I don't know if you read the sound science forum, but what we variously call burn-in, expectation bias, or just plain "getting used to something" has a noticeable effect. Whatever the source of this effect, there is a period of time required to allow our minds to "get used" to the setup before optimal results are obtained. It is equally curious to note that things usually get better with time, not worse, while things that get worse, do so immediately.)
     
    In any case, I'm just glad it's working again hah. I still have not modified a new top piece. Yeah, that means it's sitting on the bottom plexiglas tray with no top, lol. Put another way, a topless amp. [​IMG] Lol.
     
  4. Coolmeadow Kid
    No top on mine at the moment either.  I built an Oak piece for it to sit in, and I incorporated an 80mm computer fan in the top blowing down on it.  After playing for over an hour, the heat sinks were cool to the touch.  So that was a good thing to find out.  Now, if it should have some heat build up to work properly, I might need to reduce the speed of the fan.  I didn't hear anything that would make me think it changed the sound though.  Have any thoughts?
    I'm anxious to get the 2 RCA clear tops I ordered Sat. night to see if they will rival the Balwin/Raytheon long black plate that I have settled on as my best tube so far.  Then I think I'll see about doing some of the mods.  Jim.
     
  5. briancvrrbs
    Just received my cute little Bravo V2 today, and I feel like it sounds pretty good with stock, however I'm excited to hear it upgraded with IRL510, LM317A, crosstalk mod, and Mullard tube that are all on there way. Man, I love how that blue LED looks under the tube, such a nice glow [​IMG]
     
  6. Coolmeadow Kid
    WOW!!! WOW I Say!!!!  Just got 2 RCA clear tops in today.  I was leery of trying them after the long grey plate RCA I got on my original order was the least of the 3, and these are short plates instead of long plate, but I decided to follow what so many said about them as I re-read the thread last weekend.  Put the least balanced one in first (2800/2900) and I can't make myself pull it out to try the other one (2800/2800).  First few seconds, I thought it had potential.  Left it playing and came back a few minutes later and the mid-range sounded real muddy, almost distorted.  So I left it and took 3 short classes for work and came back to them. WOW!!!!!!!  It may never leave the amp.  I may just file the other one away somewhere safe in case this one dies on me! Tempted to try the two military long black plate Raytheons since I like the other Raytheon I have.  If you are on the fence about the clear tops, jump, NOW!  Jim.
     
  7. Coolmeadow Kid
    OK, a question. Scenario: I built a housing for my Bravo V2 with an 80mm computer fan in the top blowing down on the unit, top acrylic panel removed.  After 1 1/2 hour of playing music, the heat sinks were not even warm. Do some of the components need heat to work properly, or will keeping them at room temperature extend the life of the components with no degradation to sound?  I just want to make sure I'm not hurting anything.  Thanks!  Jim.
    DSCN3606.jpg
     
    money4me247 likes this.
  8. money4me247 Contributor
    @Coolmeadow Kid, omg that is ballerrr!!!! sooo coool. does it fix the staticy problem when you phone is using data nearby?
     
  9. razor5cl
    Keeping at room temperature won't hurt sound, but it might ecxtend the life of some of the components, so your setup is good.
     
  10. Coolmeadow Kid
    Thanks man.  It was a quick and dirty project.  Didn't even worry about hiding the air nail holes!  All left over Quartersawn White Oak from another project.  No plywood. Don't know about the static issue.  My computer doesn't affect it, and the fan doesn't make any noise in the amp.  I need to hook up my RF unit to the amp again and see if the pop noise is still present.  It would pop if I stood between the transmitter and receiver, but go away when I sat down beside the unit.  Thought that was weird.  Never had a cell phone next to it. Microwave and 2.4 hz cordless phone system in the house hasn't affected it  I've thought if it did I could line the inside part of the housing with foil to see if that might help.
     
     
    razor5c    Thank you for confirming that.  I'd like to do the mods, but I may wait.  If the fan keeping the components cool might extend their usable life, I'll go with that for a while.
     
    Have a good weekend!  Jim.
     
  11. money4me247 Contributor
    yea, it's only an issue when you are using mobile data nearby. smartphone 3g/4g type deal.
     
  12. Troppo
    Hi Head-Fi.org,
    I joined up as I am having an issue with the Bravo V3 I recently purchased. This thread has helped me diagnose some of the issues but so far I haven't seen anyone with my exact problem. Hopefully someone can provide some guidance!
     
    My amp has been cutting in and out on occasions, when it does I get a pop in my headphones followed by crackling and a reduction in volume. When this happens I notice the following :
     
    -> Red LED flickers.
    -> Bias voltage climbs above 14V on both channels (climbs to about 20V temporarily).
    -> If I blow air in the direction of the MOSFET's the sound eventually comes back and the bias voltage returns below 14V. Not sure if this is just coincidence or not, the temps are not abnormally high.
     
    My tube was originally biased at 11.5V on the left and 10.1V on the right, based on this thread I then adjusted the bias voltages to 13.5V as recommended  which seemed to make the problem more frequent.
     
    Whats going on here? Any ideas?
     
    I checked the voltage across the LED and it was about 1.8V from memory so I don't think its bad??
    I have reduced the Bias voltage back down to 11V to provide more headroom to the above 14V cut-out issue, is this going to create a problem?
     
    Thanks in advance,
    Nath.
     
  13. briancvrrbs
    I've already modified my Bravo V2 amp with IRL510, LM317A, and 5k trim pots. I was told that the MOSFET heatsinks would all get a bit hotter but I'm a bit worried at the amount of heat it generates.Is it normal for the IRL510s to get so hot? I also noticed the tube has gotten a bit hotter (I've set the bias on each channel to 13.5V) I can touch the MOSFET heat sinks for about two seconds until it feels like it burns and about five seconds for the tube.
     
  14. briancvrrbs
    I definitely see the improvements that came with these modifications though so I'm really liking them [​IMG]
    Also, should I do that crosstalk mod even if I'm not really bothered by it? Well, I actually havent searched for the crosstalk as I use the 3.5mm output instead of RCA
     
  15. Coolmeadow Kid

    I just did the crosstalk mod on mine....first mod I've done on it.  I'm using my desktop computer headphone out, I know, I know, not the best thing to do, but the level is set at or below midway. I used my audio card's balance to check it the other day.  Not only did both sides keep playing before, the sound got very distorted.  Just hooked it up, and doing the same thing was crystal clear and changed sides like changing the balance should do.  And I'd swear the sound is cleaner/clearer over all with normal balance set.  Listening to Pentatonix Daft Punk Medley right now.  So clean, and this is a YouTube video version! 
    Do the mod.  Make sure you have some insulated wire to use.  I think what I used is probably 22 guage I had on hand.  Cut to length, strip a small part off each end. Tin both ends with solder.  Touch to the contact point and touch with solder gun just long enough to melt solder. Just takes a second.  Be sure to hold wire still while it cools to make sure you have a good joint. Then go to the other end and repeat.  Oh man, Pentatonix Love Again is on.  Gotta go!  Jim.
     
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